D&D 5E DM needs help building monsters.

[DizzyCrash]

So I am running a ancient samurai and ninja Japanese set game.
And with the setting comes a slew of unique and deadly creatures that the monster manual does not have rules for.

So I need a little help... This is what iv built so far for the giant skeleton that bites the heads off of travelers.
I however seem to be having trouble with the bite attack. They do not seem to have a standard damage for a bite in the books. Dragons and wolves use a completely different die type with no simple conversion. I know Gargantuan creatures roll 4Die every time but I do not know the die type for many of there attacks.
( Also any other mistakes I could really use some help fixing up this beasty here )



Gashakuro
Gargantuan Humanoid


Armor Class 17 (Natural Armor)
Hit Points 240
Speed 50 ft.
Reach 20 ft


STR
23 (+6) STR
10 (+0) DEX
20 (+5) CON
7 (+2) INT
6 (-2) WIS
8 (-1) CHA


Saving Throws: Dex +5, Con +8, Wis +0
Skills: Athletics +13, Perception +4


Damage vulnerabilities bludgeoning
Damage Immunities poison
Condition Immunities exhaustion, poisoned
Senses darkvision 60 ft., passive Perception 9
Languages understands all languages it knew in life but can't speak
Challenge 1/4 (50 XP)
- 4 to AC and Attack Rolls.
+ 12 Special Attack Modifier.
+ 12 Size Bonus to Grapple Checks
Carrying Capacity + 8 times of a medium.
( Sometimes after biting it will let its victim drop )


Will Retreat after 140 Damage
Will Avoid sacred shinto words.


ACTIONS
Multiattack: Can make two attacks with hands.
Slam: +9 to hit, 4D6 + 6 ( And Knocks you 20 feet away and prone )
Engulf: Holds Player in its mouth. Blinded and Restrained. 1D10 crushing damage a turn.
Throw Rock: +9 to hit, Range 60/240 ft, ( 4D10 + 6 ) Smaller Objects are D6’s.
Bite: Deals 4D10 + 6 ( Must Be Grappled ) If it defeats you it rips off a random limb.
Siege Monster: Deals double damage to objects or structures


“Carried to its mouth in large overpowering hands… Jaws hinging open and slamming down
On your front and back sending a gout of blood spraying in every direction!”
Tipping its head back and letting the body slither into its mouth swallowing it whole. ( DC 16 Escape )

 

[Oofta]

The rules in the DMG page 273 for creating monsters are your friend. There is no "standard" bite attack for example, simply a rough guideline to how much damage a creature should do. The CR table will give you a general idea of how to build monsters. Keep in mind that you can always increase or decrease a specific aspect of a monster so that, for example they may do more damage than your target CR but have a lower AC.

Whenever I create custom monsters, I try to start with an existing monster and then build from there when I can, I find it easier.

You could also check out dmsguild.com, filter by 5E and look for "oriental". I haven't looked for this specifically but for a minimal cost you can get some pretty cool stuff.

 

[dco]

Looks good. I would not use STR bonus for a bite. CR is extremely low.
The great question is if it is well balanced to do what you want against your players, for that you can dedicate a few mins to test it.

 

[Quickleaf]

Welcome to ENWorld

So I am running a ancient samurai and ninja Japanese set game.
And with the setting comes a slew of unique and deadly creatures that the monster manual does not have rules for.

So I need a little help... This is what iv built so far for the giant skeleton that bites the heads off of travelers.
I however seem to be having trouble with the bite attack. They do not seem to have a standard damage for a bite in the books. Dragons and wolves use a completely different die type with no simple conversion. I know Gargantuan creatures roll 4Die every time but I do not know the die type for many of there attacks.
( Also any other mistakes I could really use some help fixing up this beasty here )

Wasn't familiar with this monster so I had to look up your inspiration: Gashadokuro. I highly recommend when posting a monster you want help with that you provide some information about your sources/inspiration.

For bite attacks, think of it like this...

Are its teeth like a row of needles? 1d4, like the cockatrice.
Are its teeth like a row really big needles or hollow for poison? 1d6, like a couatl.
Are its teeth like a row of daggers? 2d4, like the wolf.
Are its teeth like a row of short swords / flight arrows? 2d6, like the worg.
Are its teeth like a row of long swords / sheaf arrows? 2d8.
Are its teeth like a row of pikes? 2d10, like the hezrou.
And so on...

How do Engulf and Bite interact? Does it need to Bite Bob before it can Engulf Bob?

I will assure you that your Gashadokuro is not CR 1/4 like you have it listed....

Assuming 2 Slams per turn @ 20 dmg each = 40 DPR, with +9 attack, that's CR 7 offense.

And for defense, it has 240 HP, with effective AC 19 (due to 3 prof. saves), that's CR 12 defense.

So (7+12)/2 = 9.5, which could make it CR 9 or CR 10.

Personally, I'd round down on this monster since it doesn't have an automatic grapple attached to its attacks like many "grabby" monsters in the MM do; thus, it needs to sacrifice one of its multiattacks to make a Grapple attempt.

So, a CR 9 monster would have a proficiency bonus of +4.

That means its attack should actually by +10, and its proficient saves should be Dex +4, Con +9, Wis+2.

Also its Intelligence should be 7 (-2), not 7 (+2).

 

[Neil the Knight]

Instead of the DMG, I find this article by the Angry GM very helpful when building monsters.
http://theangrygm.com/monster-building-201-the-dd-monster-dissection-lab/

Also make sure you check out Angry's paragon monsters as well. They make for a kickass boss fight
http://theangrygm.com/elemental-boogaloo/